This invention relates to upgrading a hydrogenated oil. More particularly, a combination process is provided wherein in large part the nitrogenous component of a hydrogenated oil is reduced in size by a novel extraction of the oil, and the extracted oil is thereafter converted to a more desirable product in a separate hydrocarbon processing stage.
It is known that nitrogen compounds, when present in an oil, deleteriously affect acidic catalysts used in subsequent hydroprocessing of the oil. Usually, the nitrogenous material or residual material therefrom causes undesirable deactivation of the catalyst. Consequently a variety of treatments are taught in the art for reducing the organic nitrogenous component content of an oil. In the art of upgrading distillate oils, hydrofining or hydrotreating using a suitable catalyst is a common and frequently used expedient. The treatment produces a more-or-less satisfactory result, provided: (1) a subsequent hydroprocessing stage employs a catalyst which is relatively insensitive to nitrogen compounds, or (2) the hydrotreating conditions employed are severe enough to reduce the nitrogen content of the treated oil to a satisfactory level, for example below 10 ppmw, preferably below about 2 ppmw. There are drawbacks. The more effective (active) and desirable processing catalysts, for example those whose catalytic activity depends mainly upon Broensted acid site activity, are, in general, seriously affected by nitrogenous feed contaminants. And hydrotreating conditions severe enough to more satisfactorily reduce nitrogen levels of a treated oil usually cause conversion of an undue portion of the oil to undesirable products, such as coke, light gases, and the like. The use of such severe conditions also causes a relatively higher catalyst deactivation rate for the hydrotreating catalyst. The use of relatively moderate hydrogenating (hydrotreating) conditions, on the other hand, avoids the undesirable conversion of feedstock oil components, yet the resulting oil has an undesirable residual nitrogenous component which is relatively resistant to hydrogenation.
It is an object herein to provide an effective process for extracting residual nitrogenous components from a hydrogenated distillate oil.
A further object is to provide a combination process for upgrading a hydrogenated distillate oil by extracting a residual nitrogenous component from the oil and thereafter usefully hydroprocess the resulting oil by contacting it with an acidic hydroprocessing catalyst under suitable conditions.
A yet further object herein is to carry out the aforementioned upgrading of the distillate oil and to thereafter crack the resulting oil by contacting it with an acidic catalyst or hydrocracking catalyst under suitable conditions.
Other objects and advantages of the present invention will become apparent to those skilled in the art in the following description and illustration of the invention.